| Rapid Prototyping & Layered Manufacturing (RP & LM) technologies have been developed rapidly in the last decades. It was for prototype part fabrication originally, but now it's being investigated for fabrication of functional parts. At Rutgers, the RP & LM research group has focused on Fused Deposition (FD) methods. The sequence of fabrication steps in FD includes: filament fabrication, FD, post processing. The FD toolpath parameters alter with change of material significantly. Therefore, for a functional part to be constructed successfully, a high quality multi-material toolpath generation is critical to fabricate a perfect green part. This is the major focus of this research. A multi-material CAD system has been developed which includes single-material toolpath generation, multi-material toolpath generation, virtual simulation and void analysis sub-systems. The present development has several new important advances in FD for the first time. Multiple .stl files can be collected to create one multi-material toolpath. The intelligent toolpath features embedded include: minimum number of continuous paths, closest next starting point and extended path style. The analytical method computes void location & size. Based on the void location & size computation, adaptive roadwidth which is the largest roadwidth is obtained to satisfy the void size tolerance. Adaptive roadwidth toolpath then recalculated which makes void-free part. In multi-material system, a new feature called material offset parameter was introduced to match the intersecting material boundaries. The virtual simulation allows graphical visualization of the material deposition process. Roadshape & size can be utilized in the virtual simulation. Part quality can be predicted and analyzed from the simulation results. If needed, the toolpath parameters and/or feature selections can be altered iteratively until the virtual part quality is satisfying. The current RP & LM technologies focuses on fabricating single material part. The current development enhances the research and development toward multi-material LM CAD. |
